depressions

Depression is a term used for a range of mood disorders and related conditions. In clinical psychology, major depressive disorder involves a persistent sad mood and a loss of interest in most activities, lasting at least two weeks and accompanied by changes in sleep, appetite, energy, concentration, or self-worth. Persistent depressive disorder describes a longer-lasting, milder form. Depression can also occur as part of bipolar disorder during depressive episodes. The causes are multifactorial, including genetic, neurobiological, environmental, and psychosocial factors. Treatments typically combine evidence-based psychotherapy and pharmacotherapy, such as antidepressants, and may include lifestyle changes and social support. Early recognition and access to care improve outcomes, and individuals experiencing thoughts of self-harm should seek urgent help.

In geography and geology, a depression refers to a low area of land that is lower than the surrounding terrain. Depressions can form through tectonic subsidence, erosion, dissolution of soluble rocks, or glacial processes. They may collect surface or groundwater, creating lakes or wetlands and influencing drainage and ecosystems. Depressions range in size from small potholes to large basins and can be natural or, in some contexts, karst or structurally induced features such as sinkholes.

In meteorology, a depression denotes a low-pressure system associated with unsettled weather and, in some cases, may develop into tropical or extratropical cyclones. The term is also used historically in economics to describe severe, prolonged declines in economic activity, though such usage is less common in contemporary terminology.